FIGURE 1.

YY1 is tyrosine-phosphorylated in multiple cell types. A, cell lysates prepared from Jurkat cells treated with or without 200 μm pervanadate (Na₃VO₄) for 30 min to preserve tyrosine phosphorylation on proteins were subjected to immunoprecipitation (IP) with an anti-YY1 antibody or nonspecific IgG. Bound proteins were subjected to 10% SDS-PAGE and Western blotting (WB) with anti-phosphotyrosine (pY) or anti-YY1 antibodies. Data shown are representative of five independent experiments. B, cell lysates prepared from various cell lines treated with or without 200 μm pervanadate (Na₃VO₄) for 30 min were subjected to immunoprecipitation and Western blotting as indicated. Data shown are representative of two independent experiments. C, nuclear or cytoplasmic extract prepared from Jurkat cells treated with 200 μm pervanadate (Na₃VO₄) for 30 min were subjected to immunoprecipitation and Western blotting as indicated.